Flash photography: what is it and when to use it?

If you’ve ever seen a professional photographer in action, you’ve likely seen them using a flashlight, even during the daytime. If you’re not a professional, the thought of using a flash or strobe light can be quite intimidating at first, as it can give some hideous results, especially if you put everything on automatic. But don't worry! This article will share a few tips to help you master the flash; even in the daytime. 

What is flash photography?

Flash photography is a technique that uses a brief burst of artificial light to illuminate a subject when natural or available light is insufficient. The flash, typically produced by a built-in or external unit, helps freeze motion, reduce shadows, and reveal details that would otherwise be lost in dim conditions. 

Photographers use flash to balance exposure, highlight specific features, or create dramatic effects. While often associated with low-light environments, flash can also be used in bright settings to fill in shadows and add depth to an image.

The power of the flash

Light travels in a straight line. When it hits an object, it is reflected at the same angle. This means that having a flash on top of the camera is the worst possible place it could be, as the light emitted reflects straight back into the camera. Because of this, we have to be very careful with the power of the flash we’re using to avoid harsh highlights and overexposure of the subject.

When to use flash photography? 

Flash photography is useful in a variety of situations where natural or ambient light alone is not enough to achieve the desired result. It is often used indoors or at night to brighten a scene and make subjects more visible. Flash can also be helpful outdoors on sunny days, where it reduces harsh shadows on faces and ensures more even lighting. 

What is shutter speed? 

Shutter speed is the amount of time a camera’s shutter stays open to let light in. Fast speeds freeze motion for sharp images, while slow speeds let in more light and can create blur or artistic effects. It works alongside aperture and ISO to control exposure.

What is an aperture? 

Aperture is the opening in a camera lens that controls how much light enters the camera. It is measured in f-stops, such as f/2.8 or f/16. A wide aperture (low f-number) lets in more light and creates a shallow depth of field, which blurs the background. A narrow aperture (high f-number) allows less light and increases depth of field, keeping more of the scene in focus.

How are shutter speed aperture and flash related? 

Shutter speed, aperture, and flash work together to balance exposure in a photograph. By using a faster shutter speed (up to a maximum of around 1/200 for most cameras), you can control how much ambient light enters the camera. This allows you to darken or brighten the background, even making an overcast day look like night. The subject’s exposure is then adjusted with the flash by changing its strength or moving it closer or farther away.

Just as exposure without flash depends on aperture and shutter speed, the same applies when flash is used. Shutter speed mainly controls the amount of ambient light, while aperture determines how much of the flash light reaches the sensor. By understanding how these elements interact, photographers can create well-lit images with the right balance between background and subject.

 

Can you use flash in the daytime? 

Yes, flash can be used in the daytime, and it is often referred to as fill flash. In bright sunlight, strong shadows can appear on a subject’s face or background. Using flash helps soften those shadows, making the lighting more even and the details clearer. Flash can also help balance exposure when the subject is backlit, preventing them from appearing too dark against a bright background. 

Become a professional Photographer at the Institute of Creative Design

Flash photography may seem daunting at first, but once you understand how it works with shutter speed and aperture, it becomes a powerful creative tool. Whether you are shooting indoors, outdoors, at night, or even in bright daylight, knowing when and how to use flash can dramatically improve your images. 

By practicing with different settings and experimenting with light, you’ll not only avoid harsh or unflattering results but also gain the ability to control mood, highlight details, and bring balance to your photos. Ultimately, flash is less about overpowering a scene and more about giving you control over how your subject and background come together in a perfectly exposed shot.

If you are interested in learning about photography or becoming a professional Photographer, have a look at our industry-accredited courses.

FAQ

What is the rule for flash photography?

The general rule is to use flash only when it improves the photo without disturbing the environment. Technically, balance flash with shutter speed and aperture so the subject is well lit and the background looks natural. Practically, always follow venue guidelines, avoid pointing flash directly at people or animals at close range, and use it thoughtfully to enhance rather than overpower a scene.

Why is flash photography not allowed?

Flash photography is often restricted in museums, theaters, and events because the bright light can damage sensitive artwork, distract performers, or disturb other visitors. In some cases, it’s also a safety concern, as sudden flashes can startle people or animals.

What ISO should I use with flash? 

When using flash, keep ISO low (around 100–400) to reduce noise and keep images clean. Raise ISO only if you need more background light or are shooting in very dark conditions.